Project ID: 2007PR35BTitle: Waste Tire Crumb Rubber as Sorbent for Heavy Metal Ions: A Field Case-StudyProject Type: ResearchStart Date: 3/01/2007End Date: 2/28/2008Congressional District:Focus Categories: Treatment, Toxic Substances, Water QualityKeywords: water treatment, water quality, heavy metalsPrincipal Investigators: Perales-Perez, Oscar J; Roman, FelixFederal Funds: $ 18,000Non-Federal Matching Funds: $ 5,503Abstract: The present approach is based on the verified capability of waste tire crumb rubber to remove hazardous species from aqueous solutions. Our laboratory-scale results have demonstrated the capability of waste tire crumb rubber to remove inorganic Cu(II), Cd(II) and Pb(II) species from synthetic aqueous solutions. Crumb rubber already cleaned and downsized to different particle sizes, was kindly donated by Rubber Recycling and Manufacturing Corp., REMA, a Puerto Rican company that produces crumb rubber from scrap tires. The sorption property of crumb rubber is attributed to its main components: carbon black, zinc oxide and sulfur, all embedded in an elastomeric matrix. The success of the application of waste tire crumb rubber as sorbent for heavy metal ions paves the way to determine its applicability to clean-up real effluents. The presence of Cu, Pb and Zn species in the final discharge generated at the water filtration facility in Mayagüez (as stated by the AAA, the Puerto Rican Agency in charge of potable water facilities) represents an incomparable opportunity to test the capability of crumb rubber to solve an actual environmental problem. Accordingly, this proposal deals with the evaluation of the applicability of crumb rubber to remove Cd, Pb and Zn species contained in the final discharge generated at the AAA-Mayagüez water filtration facility, herewith called the "final discharge". We propose, first, to determine the relative fraction of dissolved metal ions in the mentioned discharge and, next, to investigate the conditions leading to maximization of the uptake capacity and sorption rate of pollutants as well as the conditions to re-extract them (desorption), a factor of critical importance to determine the potential use of the proposed sorbent on a large scale remediation application. The metal ions removal efficiency and the corresponding up-take capacities will be determined and used to propose a tentative flow-sheet that will include a heavy metal ions removal stage. Proposed flow-sheet must be compatible with current operation at the water filtration facility.

The methodology proposed can lead to benefits that will significantly impact the fields of environmental protection technologies and recycling in Puerto Rico, The United States and the whole international community. The major benefit will be the on-field application of crumb rubber as an inexpensive and efficient sorbent for toxic metals. Based on the technical and social importance of the involved fields (cleaning of polluted water and recycling of waste tires), the national impact of the present work becomes evident. Based on the results from batch and columnar tests, process options including filter beds or cleaning columns containing packed granular crumb rubber, can be proposed. The results of this investigation will expand the usage of the crumb rubber and benefit directly the crumb-rubber recycling companies located on the Island (e.g., REMA, Inc) and present new options for the local and federal government agencies dealing with water treatment.